Various imaging procedures are available to generate multiple two-dimensional cross-sectional images of tissue and three-dimensional reconstruct-ions. These images are used for many purposes, including for diagnosis of illness, planning of medical procedures and for research and investigation generally. Magnetic Resonance Imaging (MRI) is one such imaging procedure.
In order to enhance the quality of the MRI images, the object to be imaged, for example part of a patient's body, is placed within a structure known in the industry as an “imaging coil.” Imaging coils useful in MRI are available from commercial sources such as General Electric® and Siemens® Medical Solutions USA. The imaging coil is a one or two-piece assembly that encloses an antenna array, or coil, which speeds MRI imaging and enhances MRI image clarity. The imaging coil is positioned closely around the object to be imaged. The imaging coil and object to be imaged are then positioned inside the “tunnel” portion of an MRI machine for generation of the MRI images.
For at least MRI imaging purposes, it is important that the object to be imaged is properly positioned within the imaging coil. A proper position is a position within the imaging coil in which the object to be imaged is fully surrounded by the antenna enclosed within the imaging coil. Consistent, proper positioning of the object to be imaged facilitates locating of the tissue or thing which is of interest, thereby contributing to more efficacious treatments and therapies.
And, as can be appreciated, the object to be imaged should not move during the imaging process. Limitation of movement is required to generate clear, accurate images. In health-care applications, patient movement is a frequent problem that results in corrupt images and extended imaging procedure times. Such complications diminish the quality of patient care and increase cost.
In the health-care context, a number of devices are presently used with imaging coils to both position the patient within the imaging coil and limit patient movement. Representative devices are sterotactic frames and thermoplastic immobilization masks. A stereotactic frame is a type of head enclosure which is secured directly to the patient's head and which prevents head movement. A thermoplastic mask is further type of head enclosure in which a shrink fit between the mask and the patient's head limits head movement. Fiducial markers visible in the generated MRI image are typically attached to both types patient-immobilization devices to facilitate location of the tissue of interest. With both types of devices, the device and patient's head are placed within the imaging coil in order to perform the imaging procedure.
Even with the use of patient-immobilization devices such as those described, problems remain with respect to positioning of the patient within the imaging coil and limiting patient movement. One problem is that the patient-immobilization device typically has a shape, size and configuration which is not complementary to that of the imaging coil. For instance, a patient-immobilization device from one source may not be compatible with an imaging coil from another source. In order to provide the desired compatibility, it would be necessary to modify the “off-the-shelf” imaging coil supplied by the manufacturer in some way. Such imaging coil modification is costly and may be ineffective. As a result of such incompatibility, it may be difficult to consistently position the patient-immobilization device at the desired proper position within the imaging coil. And, the patient-immobilization device may move within the imaging coil, potentially corrupting the image, should the patient shift position during the imaging process.
Furthermore, it is a challenge to fit a patient-immobilization device of the type previously described to the patient and to transport and position the patient in the imaging coil while fitted with the patient-immobilization device. It is highly desirable to avoid contact between the patient immobilization device and the imaging coil during patient positioning so as to avoid unnecessary patient discomfort. Even if a patient-immobilization device were not used, the nature of the patient's condition (e.g. head or neck injury) may make it difficult to position the patient within the imaging coil. The capability to perform as much preparatory positioning of the patient at a position outside the imaging coil followed by ease of patient movement to the proper position within the coil is desirable.
One solution to some of the foregoing problems is provided by the Special Procedures Headcoil system sold by Midwest RF, LLC of Hartland, Wis., a related company of the applicant. The Special Procedures Headcoil is an imaging coil which is specially-manufactured to receive an insert to which a stereotactic frame or thermoplastic immobilization mask as described above is attached. The Special Procedures Headcoil is manufactured with a specially-formed pocket corresponding to the shape of the insert which receives the insert so that the insert and stereotactic frame or thermoplastic immobilization mask are temporarily held in place.
The Special Procedures Headcoil system is highly effective for its intended purpose. However, the insert for supporting the stereotactic frame or thermoplastic immobilization mask has a headcoil-specific shape which is not compatible with off-the-shelf imaging coils from manufacturers other than Midwest RF and, therefore, cannot be used to secure a patient's head or other object at a desired position within such other imaging coils. And, it is difficult for the medical professional to see the position of the insert because the insert is completely enclosed by the Special Procedures Headcoil. Finally, the insert does not include easily accessible gripping surfaces to facilitate lifting of the insert from the headcoil by the medical professional who is assisting the patient with the imaging procedure.
It would be an improvement in the art to provide apparatus which would improve patient care, which would make it easier to position a patient in an imaging coil, which would facilitate generation of better images and which would be capable of use with a broad range of unmodified, off-the-shelf MRI imaging coils and other imaging coil types.